Configuration Space Analysis of the Specific Rotation of Helicenes

Aharon, Tal; Caricato, Marco

doi:10.1021/acs.jpca.9b01823

Cited by 15 publications

(29 citation statements)

References 62 publications

(117 reference statements)

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“…Thus, we recommend either the RG5 or AS5 criteria as the best compromise between computational cost and accuracy (the RS5 criterion would be more accurate but also more computationally intensive). We note that the analysis performed in this work is based on canonical MOs, which may or may not represent the most compact representation of the OR tensor . It would be interesting to repeat this analysis using a localized MO basis, but the CPKS code in GAUSSIAN is only available in the canonical MO basis, thus beyond the scope of this work,…”

Section: Discussionmentioning

confidence: 99%

“…(64) in Pople et al, to start the solution of Equation . Thus, we can use the guess P S to define two possible criteria for the MO selection, one based on the square elements of the guess matrix:

{G^{1}}_{ia} \equiv \sum_{β} {|P_{β, italicia}^{S}|}^{2},

and one based on the dot product with the conjugate dipole integrals:

{G^{2}}_{ia} \equiv {\overset{false~}{S}}_{ia} = Im ({}, \sum_{β} P_{β, italicai}^{S} {(R_{β, italicai})}^{*}),

where we have used the

\overset{S}{true}

symbol to connect this quantity with the rotatory strength in configuration space, which we defined for the qualitative analysis of the MO transition contributions to the OR tensor . The difference here is that the

\overset{S}{true}

values are computed with the guess density rather than the converged density.…”

Section: Theory and Computational Detailsmentioning

confidence: 99%

“…tity with the rotatory strength in configuration space, which we defined for the qualitative analysis of the MO transition contributions to the OR tensor. [28][29][30] The difference here is that theS values are computed with the guess density rather than the converged density. In particular, we solve the CPKS equations for the magnetic dipole perturbation, so that S = m and R = μ in Equations (5) and (6).…”

Section: Theory and Computational Detailsmentioning

confidence: 99%

“…In this work, we present a different approach to reduce the cost of [ α ] ω calculations with Kohn‐Sham DFT (KS‐DFT), based on the selection of the molecular orbitals (MOs) that are likely to contribute the most to this property and discarding the rest. We have recently shown that a significant portion of the MOs do not contribute significantly to [ α ] ω through a post‐calculation analysis of the OR tensor . Here, we try to determine the meaningful MOs beforehand and to solve the linear response equations only with a subset of relevant MOs while preserving accuracy.…”

Section: Introductionmentioning

confidence: 99%

“…We have recently shown that a significant portion of the MOs do not contribute significantly to [α] ω through a post-calculation analysis of the OR tensor. [28][29][30] Here, we try to determine the meaningful MOs beforehand and to solve the linear response equations only with a subset of relevant MOs while preserving accuracy.…”

Section: Introductionmentioning

confidence: 99%

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A molecular orbital selection approach for fast calculations of specific rotation with density functional theory

Aharon

Caricato

2019

Chirality

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In this work, we describe a simple approach to select the most important molecular orbitals (MOs) to compute the optical rotation tensor through linear response (LR) Kohn‐Sham density functional theory (KS‐DFT). Taking advantage of the iterative nature of the algorithms commonly used to solve the LR equations, we select the MOs with contributions to the guess perturbed density that are larger than a certain threshold and solve the LR equations with the selected MOs only. We propose two criteria for the selection, and two definitions of the selection threshold. We then test the approach with two functionals (B3LYP and CAM‐B3LYP) and two basis sets (aug‐cc‐pVDZ and aug‐cc‐pVTZ) on a set of 51 organic molecules with specific rotation spanning five orders of magnitude, 100–104 deg (dm−1 (g/mL)−1). We show that this approach indeed can provide very accurate values of specific rotation with estimated speedup that ranges from 2 to 8× with the most conservative selection criterion, and up to 20 to 30× with the intermediate criterion.

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Section: Discussionmentioning

confidence: 99%

{G^{1}}_{ia} \equiv \sum_{β} {|P_{β, italicia}^{S}|}^{2},

and one based on the dot product with the conjugate dipole integrals:

{G^{2}}_{ia} \equiv {\overset{false~}{S}}_{ia} = Im ({}, \sum_{β} P_{β, italicai}^{S} {(R_{β, italicai})}^{*}),

where we have used the

\overset{S}{true}

\overset{S}{true}

values are computed with the guess density rather than the converged density.…”

Section: Theory and Computational Detailsmentioning

confidence: 99%

Section: Theory and Computational Detailsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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A molecular orbital selection approach for fast calculations of specific rotation with density functional theory

Aharon

Caricato

2019

Chirality

Self Cite

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On the choice of coordinate origin in length gauge optical rotation calculations

2023

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In this work, we explore the issue of origin dependence in optical rotation (OR) calculations in the length dipole gauge (LG) using standard approximate methods belonging to density functional theory (DFT) and coupled cluster (CC) theory. We use the origin‐invariant LG approach, LG(OI), that we recently proposed as reference for the calculations, and we study whether a proper choice of coordinate origin and molecular orientation can be made such that diagonal elements of the LG‐OR tensor match those of the LG(OI) tensor. Using a numerical search algorithm, we show that multiple spatial orientations can be found where the LG and LG(OI) results match. However, a simple analytical procedure provides a spatial orientation where the origin of the coordinate system is close to the center of mass of the molecule. At the same time, we also show that putting the origin at the center of mass is not an ideal choice for every molecule (relative errors in the OR up to 70% can be obtained in out test set). Finally, we show that the choice of coordinate origin based on the analytical procedure is transferable across different methods and it is superior to putting the origin in the center of mass or center of nuclear charge. This is important because the LG(OI) approach is trivial to implement for DFT, but not necessarily for nonvariational methods in the CC family. Therefore, one can determine an optimal coordinate origin at DFT level and use it for standard LG‐CC response calculations.

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Origin invariant molecular orbital decomposition of optical rotation

Balduf

Caricato²

2023

Theor Chem Acc

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Configuration Space Analysis of the Specific Rotation of Helicenes

Cited by 15 publications

References 62 publications

A molecular orbital selection approach for fast calculations of specific rotation with density functional theory

A molecular orbital selection approach for fast calculations of specific rotation with density functional theory

On the choice of coordinate origin in length gauge optical rotation calculations

Origin invariant molecular orbital decomposition of optical rotation

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